[squid-users] Filtering HTTPS URLs

[Amos Jeffries]

On 6/05/2016 5:51 p.m., Victor Hugo wrote:
> Here's a strange one for you though, if I change:
> acl whitelist-regex url_regex -i reddit.com/r/news
> 
> to:
> acl whitelist-regex url_regex -i reddit\.com\/r\/news www\.reddit\.com\:443
> 
> it works every 2nd time but the match is too greedy and allows
> www.reddit.com/r/anything every 2nd time.
> 

That first regex pattern requires a path "/r/news" to exist. CONNECT
messages do not have paths.

That second pattern you are now adding matches (and thus allows) the
CONNECT message authority-URI built from the traffic SNI details.

They are two different regex patterns so if *either one* matches the ACL
test will be a match.


Try adding this line *after* the default "deny CONNECT !SSL_ports" line:
 acl reddit dstdomain .reddit.com
 http_access allow CONNECT SSL_ports reddit

That should allow the CONNECT's stuff to happen and your ssl_bump and
http_access rules then handle the HTTPS.


Amos


> Victor
> 
> it
> 
> On Thu, Feb 11, 2016 at 10:05 AM, Victor Hugo <fourtrials at gmail.com> wrote:
> 
>> Hi,
>>
>> I was wondering if it is possible to filter HTTPS URLs using squid (for
>> example to blacklist reddit.com but allow https://www.reddit.com/r/news/)?
>>
>> I thought this may be possible using ssl_bump and url_regex. I have been
>> trying this using squid 3.5.13 but with no success.
>>
>> Here is the squid configuration that I have tried but doesn't seem to work
>> (it works for http sites though):
>>
>> acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
>> acl localnet src 172.16.0.0/12 # RFC1918 possible internal network
>> acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
>> acl localnet src fc00::/7       # RFC 4193 local private network range
>> acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged)
>> machines
>>
>> acl SSL_ports port 443
>> acl Safe_ports port 80 # http
>> acl Safe_ports port 21 # ftp
>> acl Safe_ports port 443 # https
>> acl Safe_ports port 70 # gopher
>> acl Safe_ports port 210 # wais
>> acl Safe_ports port 1025-65535 # unregistered ports
>> acl Safe_ports port 280 # http-mgmt
>> acl Safe_ports port 488 # gss-http
>> acl Safe_ports port 591 # filemaker
>> acl Safe_ports port 777 # multiling http
>> acl CONNECT method CONNECT
>>
>> http_access deny !Safe_ports
>> http_access deny CONNECT !SSL_ports
>> http_access allow localhost manager
>> http_access deny manager
>>
>> acl whitelist-regex url_regex -i reddit.com/r/news
>> http_port 3129 ssl-bump
>> cert=/opt/squid-3.5.13/etc/squid3/ssl_cert/myCA.pem
>> generate-host-certificates=on dynamic_cert_mem_cache_size=4MB
>> acl bump_sites ssl::server_name .reddit.com
>> ssl_bump bump bump_sites
>> ssl_bump splice !bump_sites
>> http_access allow whitelist-regex
>> http_access allow localhost
>> http_access deny all
>> coredump_dir /opt/squid-3.5.13/var/spool/squid3
>> refresh_pattern ^ftp: 1440 20% 10080
>> refresh_pattern ^gopher: 1440 0% 1440
>> refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
>> refresh_pattern . 0 20% 4320
>> pinger_enable off
>> Relevant access.log output (IP addresses redacted to x.x.x.x):
>> 1455145755.589      0 x.x.x.x TCP_DENIED/200 0 CONNECT www.reddit.com:443
>> - HIER_NONE/- -
>> 1455145755.669      0 x.x.x.x TAG_NONE/403 4011 GET
>> https://www.reddit.com/r/news - HIER_NONE/- text/html
>> 1455145755.782      0 x.x.x.x TCP_DENIED/200 0 CONNECT www.reddit.com:443
>> - HIER_NONE/- -
>>
>> I don't want to whitelist the dstdomain .reddit.com
>> (i.e whitelist-ssldomain dstdomain .reddit.com) as that would allow
>> access to all of the other subreddits.
>>
>> Appreciate any help or suggestions you have. Thanks.
>>
>> Victor
>>
>